On Thursday, the company said that after three days of talks with the International Association of Machinists and Aerospace Workers, the union shot down its “best and final” offer. In November, the union rejected an earlier contract proposal that would have guaranteed worker jobs for eight years in exchange for converting traditional pensions into 401(k) retirement plans, the Los Angeles Times notes.

Boeing has threatened to move production of its new commercial jet outside of Washington if it cannot secure deals for tax incentives from state politicians and union contracts. It says it is currently reviewing offers from 22 other states for sites to build the jet.

Washington officials had already agreed to a deal to keep assembly of the 777X jet in the state. However, if Boeing does not secure an agreement with the union, the company could move production elsewhere.

The loss of 777X assembly could leave a deep mark in the state’s economy, especially around Seattle.